Articles by Sébastien Meghezi in JoVE
Engineering 3D Cellularized Collagen Gels for Vascular Tissue Regeneration Sébastien Meghezi1, Dawit G. Seifu1,2, Nina Bono1,3, Larry Unsworth2,4,5, Kibret Mequanint6, Diego Mantovani1,2 1Laboratory for Biomaterials and Bioengineering, Department Min-Met-Materials Eng & CHU de Québec Research Center, Canada Research Chair I for the Innovation in Surgery, Laval University, 2NSERC CREATE Program for Regenerative Medicine (NCPRM), Laval University, 3Department Electronics, Information and Bioengineering, Politecnico di Milano, 4Department of Chemical and Materials Engineering, University of Alberta, 5National Institute for Nanotechnology, National Research Council (Canada), 6Department of Chemical and Biochemical Engineering, University of Western Ontario In this work, we present a technique for the rapid fabrication of living vascular tissues by direct culturing of collagen, smooth muscle cells and endothelial cells. In addition, a new protocol for the mechanical characterization of engineered vascular tissues is described.
Other articles by Sébastien Meghezi on PubMed
Fetal Development, Mechanobiology and Optimal Control Processes Can Improve Vascular Tissue Regeneration in Bioreactors: an Integrative Review Medical Engineering & Physics. Apr, 2012 | Pubmed ID: 22133487 Vascular tissue engineering aims to regenerate blood vessels to replace diseased arteries for cardiovascular patients. With the scaffold-based approach, cells are seeded on a scaffold showing specific properties and are expected to proliferate and self-organize into a functional vascular tissue. Bioreactors can significantly contribute to this objective by providing a suitable environment for the maturation of the tissue engineered blood vessel. It is recognized from the mechanotransduction principles that mechanical stimuli can influence the protein synthesis of the extra-cellular matrix thus leading to maturation and organization of the tissues. Up to date, no bioreactor is especially conceived to take advantage of the mechanobiology and optimize the construct maturation through an advanced control strategy. In this review, experimental strategies in the field of vascular tissue engineering are detailed, and a new approach inspired by fetal development, mechanobiology and optimal control paradigms is proposed. In this new approach, the culture conditions (i.e. flow, circumferential strain, pressure frequency, and others) are supposed to dynamically evolve to match the maturity of vascular constructs and maximize the efficiency of the regeneration process. Moreover, this approach allows the investigation of the mechanisms of growth, remodeling and mechanotransduction during the culture.
Effects of a Pseudophysiological Environment on the Elastic and Viscoelastic Properties of Collagen Gels International Journal of Biomaterials. 2012 | Pubmed ID: 22844285 Vascular tissue engineering focuses on the replacement of diseased small-diameter blood vessels with a diameter less than 6 mm for which adequate substitutes still do not exist. One approach to vascular tissue engineering is to culture vascular cells on a scaffold in a bioreactor. The bioreactor establishes pseudophysiological conditions for culture (medium culture, 37°C, mechanical stimulation). Collagen gels are widely used as scaffolds for tissue regeneration due to their biological properties; however, they exhibit low mechanical properties. Mechanical characterization of these scaffolds requires establishing the conditions of testing in regard to the conditions set in the bioreactor. The effects of different parameters used during mechanical testing on the collagen gels were evaluated in terms of mechanical and viscoelastic properties. Thus, a factorial experiment was adopted, and three relevant factors were considered: temperature (23°C or 37°C), hydration (aqueous saline solution or air), and mechanical preconditioning (with or without). Statistical analyses showed significant effects of these factors on the mechanical properties which were assessed by tensile tests as well as stress relaxation tests. The last tests provide a more consistent understanding of the gels' viscoelastic properties. Therefore, performing mechanical analyses on hydrogels requires setting an adequate environment in terms of temperature and aqueous saline solution as well as choosing the adequate test.